Effect of TiN-Particles on Fracture of Press-Hardened Steel Sheets and Components

Pang, J. C.; Yi, Hong; Lu, Qi; Enloe, Charles M.; Wang, Jeff

doi:10.1007/s11837-018-3308-z

Cited by 15 publications

(5 citation statements)

References 15 publications

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“…So that TiN particles are formed, and the formation of BN can be avoided. Otherwise, B would be consumed, reducing hardenability and deteriorating the mechanical properties of hot-stamping steels [40,41]. In addition, excess Ti reacts with other microalloying elements to trigger co-precipitation of particles, e.g.…”

Section: Resultsmentioning

confidence: 99%

Precipitation behaviour and strengthening mechanisms of V-bearing 1800 MPa grade hot-stamping steel

Cheng

Wang

Liu

et al. 2023

Materials Science and Technology

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Achieving strength-ductility synergy of hot-stamping steel via microalloying technology has attracted great attention due to their pronounced precipitation strengthening. Nevertheless, the precipitation behaviours and characteristics have not been clearly unveiled. In this work, the effects of V content on the microstructure and mechanical properties of 1800 MPa grade hot-stamping steel are systematically studied. Massive V contained precipitates develop after hot-rolling and coiling, which refine the martensitic microstructure and retain in the matrix after austenitizing and quenching. The refined martensite with massive precipitates is responsible for the good mechanical properties. Generally, the tensile strength decreases slightly with increasing V content from 0.04% to 0.2%, as V consumes C in the martensite matrix by forming carbides and promoting precipitate coarsening.

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Section: Resultsmentioning

confidence: 99%

Precipitation behaviour and strengthening mechanisms of V-bearing 1800 MPa grade hot-stamping steel

Cheng

Wang

Liu

et al. 2023

Materials Science and Technology

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“…Large, cuboidal TiN acts as a local stress concentrator and, thus, deteriorates toughness and bendability. [15,20,31] Although 20MnB8 contains a higher amount of nitrogen, size and number density of nitrides are only slightly enhanced compared with 22MnB5. Also, the size distribution is comparable, revealing that in both steels, the majority of the TiN is equal to or smaller than an ECD of 1.5 μm (Figure 5).…”

Section: Discussionmentioning

confidence: 99%

Bending Behavior of Zinc‐Coated Hot Stamping Steels

Hofer

Stadler

Kurz

et al. 2021

steel research int.

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The contradictory requirements of increased passenger safety and a simultaneous mass reduction of the body-in-white drive the development of advanced high strength steels in the automotive industry. Especially, components for the safety cell, e.g., reinforcement of B-pillar, bumper, and roof rails, need to be rigid and impede intrusion in the case of a crash event to protect the occupants. [1] For these applications, ultrahigh strength steels with a tensile strength (TS) of up to 2000 MPa and a martensitic microstructure are used. [2] However, their exceptional high strength is accompanied by limited formability, which can be overcome by hot stamping. The combination of shaping by hot forming and the simultaneous microstructure adjustment by quenching in water-cooled dies enables the production of components with complex geometries. Besides the reduced press forces, this manufacturing process also offers the ability to produce tailored blanks and eliminate spring back, which increases with the sheet strength in cold-forming operations. [3,4] While hot stamping was initially used for built-in components, the expansion of their application to more exposed structures leads to the need for corrosion protection. [5] In contrast to AlSi coatings that only provide barrier protection, zinc coatings additionally offer cathodic corrosion protection and, therefore, maintain their protection effect even when the coating layer is breached, e.g., by stone chipping. The major drawback of zinc coatings is their susceptibility to liquid metal embrittlement (LME) during direct hot press forming due to the presence of liquid zinc during deformation. [6] Thus, zinc-coated press hardening steels are mainly produced via the "indirect" process, where the sheet is cold stamped and subsequently subjected to a quenching and calibration operation in the press after full austenitization. Another possibility to avoid LME is by elimination of liquid phases during hot forming. One idea is to increase austenitization time to fully transform the coating into a single-phase solid solution of α-Fe(Zn) ferrite. [7] The disadvantage of this approach, besides the longer process time, is the decreased corrosion protection due to the lower potential difference between matrix and α-Fe(Zn) ferrite compared with zinc-rich Γ-ZnFe. [8] A further possibility is to increase the transfer time [9] or add an additional precooling step [8,10] to solidify all zinc phases, i.e., Γ-ZnFe, prior to the stamping operation. Typical precooling temperatures range between 450 and 650 C. [11] To guarantee a stable process, the composition of the standard hot stamping alloy 22MnB5 has been slightly adapted to 20MnB8. An increased amount of

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“…Järvinen et al [ 39 ] found 0.15% Ti addition in 34MnB5 steel can improve the bending angle from 55° to 60.0°. In contrast, Pang et al [ 80 ] found that Ti may deteriorate the bending properties by forming micron-sized TiN particles when the N content is not well controlled in 22MnB5 steel. Impact toughness is another parameter to identify the fracture toughness of PHS.…”

Section: Traditional Mn-b Steelsmentioning

confidence: 97%

Multi-Scale Microstructural Tailoring and Associated Properties of Press-Hardened Steels: A Review

et al. 2023

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High-strength press-hardened steels (PHS) are highly desired in the automotive industry to meet the requirement of carbon neutrality. This review aims to provide a systematic study of the relationship between multi-scale microstructural tailoring and the mechanical behavior and other service performance of PHS. It begins with a brief introduction to the background of PHS, followed by an in-depth description of the strategies used to enhance their properties. These strategies are categorized into traditional Mn-B steels and novel PHS. For traditional Mn-B steels, extensive research has verified that the addition of microalloying elements can refine the microstructure of PHS, resulting in improved mechanical properties, hydrogen embrittlement resistance, and other service performance. In the case of novel PHS, recent progress has principally demonstrated that the novel composition of steels coupling with innovative thermomechanical processing can obtain multi-phase structure and superior mechanical properties compared with traditional Mn-B steels, and their effect on oxidation resistance is highlighted. Finally, the review offers an outlook on the future development of PHS from the perspective of academic research and industrial applications.

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Effect of TiN-Particles on Fracture of Press-Hardened Steel Sheets and Components

Cited by 15 publications

References 15 publications

Precipitation behaviour and strengthening mechanisms of V-bearing 1800 MPa grade hot-stamping steel

Precipitation behaviour and strengthening mechanisms of V-bearing 1800 MPa grade hot-stamping steel

Bending Behavior of Zinc‐Coated Hot Stamping Steels

Multi-Scale Microstructural Tailoring and Associated Properties of Press-Hardened Steels: A Review

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